If you're using a newer browser, there should be a date picker which makes things easy. Sounds like you aren't, though. (Nothing wrong with that!) You can still enter dates, but they have to be entered manually in a "computer format" which is YYYY-MM-DD.

If you can upgrade your browser (assuming you aren't on a computer that can't be upgraded), that will make a number of things easier to do on this website and is highly recommended. *nodding*

-- Ryan